INPUT/OUTPUT CONNECTIONS

PLASTIC DIP PACKAGE

PIN

FUNCTION

PIN

FUNCTION

BIT 1 (MSB)

MINV

BIT 2

BIT 3

BIT 4

ANALOG GND

DIGITAL GND

NO CONNECT

+5V POWER

ANALOG INPUT

5.2V POWER

NO CONNECT

5.2V POWER

ANALOG INPUT

5.2V POWER

NO CONNECT

+5V POWER

ANALOG GND

DIGITAL GND

LINV

CLOCK INPUT

BIT 5

BIT 8 (LSB)

BIT 6

BIT 7

FEATURES

8-bit resolution

20MHz conversion rate

±1/2LSB maximum nonlinearity

8MHz input bandwidth

Low power consumption, 375mW

TTL compatible

Single or dual supply operation

GENERAL DESCRIPTION

Datel's ADC-304 is an 8-bit, 20MHz analog-to-digital flash
converter. The ADC-304 offers many performance features not
obtainable from other flash A/D's.

Key reatures include a low power dissipation of 375mW and
TTL-compatible outputs. A wide analog input bandwidth of
8MHz (3dB) allows operation without the need of a sample-
hold. Also, single +5V supply operation is obtainable with an
input range of +3 to +5V, eliminating the need for an additional
power supply. A 0 to 2V input range is available with ±5V
supply operation.

Another novel feature of the ADC-304 is its user-selectable
output coding. The MINV and LINV pins allow selection of
binary, complementary binary, and if external offset circuitry is
used for bipolar inputs, offset binary, two's complement and
complementary two's complement coding.

The ADC-304 is supplied in a 28-pin plastic DIP or a 28-pin
plastic SOP package. Operating temperature range is 20 to
+75°C. Storage temperature range is 55 to +150°C.

INPUT/OUTPUT CONNECTIONS

PLASTIC SOP PACKAGE

PIN

FUNCTION

PIN

FUNCTION

ANALOG INPUT

SENSE

ANALOG GND

CLOCK INPUT

NO CONNECT

BIT 8 (LSB)

MINV

BIT 7

BIT 1 (MSB)

BIT 6

BIT 2

BIT 5

BIT 3

LINV

BIT 4

DIGITAL GND

+5V POWER

OVERRANGE

5.2V POWER

Figure 1. ADC-304 Functional Block Diagram

IN N O VA T IO N a n d E X C E L L E N C E

BIT 1 (MSB)

BIT 2

BIT 3

BIT 4

OVERRANGE

CLOCK

INPUT

BIT 8 (LSB)

LINV

BIT 7

BIT 6

BIT 5

ANALOG

INPUT

SENSE

R/2

-
T

-
2

I
T

-
T

-
8

I
T

COMPARATOR

LATCH

256

129

128

SENSE

MINV

THESE PINS ARE AVAILABLE ON SOP PACKAGE ONLY

ANALOG

INPUT

ADC-304

8-Bit, 20MHz, Low-Power

Flash A/D Converters

DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.)

Tel: (508) 339-3000 Fax: (508) 339-6356

For immediate assistance (800) 233-2765

ADC-304

FUNCTIONAL SPECIFICATIONS

Unless otherwise noted, the following specifications apply to the ADC-304 when used
either with a single or dual power source. The test conditions are:

For single power supply operation:

For dual power supply operation:

= +5V, DIG GND = 0V

= 0V, V

= +5V

= 5.2V, V

= 0V,

= +3V, T

= +25°C

= 2V, T

= +25°C

ANA GND = +5V, f

= 20MHz

ANA GND = 0V, f

= 20MHz

ANALOG INPUTS

MIN.

TYP.

MAX.

UNITS

Input Range

Volts

Input Capacitance

Input Bias Current

100

µA

Offset Voltage

+11

DIGITAL INPUTS

Logic Levels

Logic "1"

+2.0

Volts

Logic "0"

+0.8

Volts

Logic Input Currents

Logic "1"

100

150

µA

Logic "0"

0.1

0.32

0.5

PERFORMANCE

Conversion Rate

MHz

Integral Nonlinearity

±1/2

LSB

Differential Nonlinearity

±1/2

LSB

Differential Gain Error

1.5

Differential Phase Error

0.5

degrees

Aperture Delay Ta

Aperture Uncertainty

Signal-to-Noise and Distortion

= full scale, f

= 20MHz)

= 1MHz

= 5MHz

= 10MHz

Clock Pulse Width

Tpw1

Tpw0

Reference Pin Current

Reference Resistance (V

to V

)

130

Ohms

Reference Input (dual supply)

0.1

+0.1

Volts

1.8

2.0

2.2

Volts

Footnotes:

= 1kHz, ramp

NTSC 40 IRE-modulated ramp, f

= 14.3MHz

ABSOLUTE MAXIMUM RATINGS

PARAMETERS

LIMITS

UNITS

Supply Voltages

to GND

0 to +6

Volts

to GND

0 to 6

Volts

Input Voltage (Analog)

Vin

to (ANA GND + 0.3)

Volts

(dual power supply)

Input Voltage (Reference) V

, V

to (ANA GND + 0.3)

Volts

(dual power supply)

2.5

Volts

Input Current

3.0 to +3.0

Input Voltage (Digital)

Digital Inputs

0.5 to +V

Volts

DIGITAL OUTPUTS

MIN.

TYP.

MAX.

UNITS

Resolution and Output Coding

bits

Straight binary

Complementary binary

Two's complement

Complementary two's complement

Logic Levels

Logic "1"

+2.7

+3.4

Volts

Logic "0"

+0.5

Volts

Logic Loading "1"

500

µA

Logic Loading "0"

Output Data Delay

TDLH

TDHL

POWER REQUIREMENTS

Single Power Supply

Supply Voltage = +V

+4.75

+5.0

+5.25

Volts

Supply Voltage = V

Volts

Supply Current = +I

+56

+71

+91

Power Dissipation

280

355

455

Dual Power Supply

Supply Voltage = +V

+4.75

+5.0

+5.25

Volts

Supply Voltage = V

4.75

5.2

5.5

Volts

Supply Current = +I

+10

+14

Supply Current = I

Power Dissipation

295

375

476

PHYSICAL/ENVIRONMENTAL

Operating Temperature

+75

°C

Storage Temperature

+150

°C

TECHNICAL NOTES

1. The two DIGITAL GND pins (pins 5 and 11 on the DIP, pins

12 and 18 on the SOP) are not connected to each other
internally and neither are the two +5V POWER pins (6 and
10 on the DIP, 13 and 17 on the SOP). All four pins must be
externally connected to the appropriate pcb patterns. Also,
the DIGITAL GND and ANALOG GND pins are not
connected to each other internally.

2. Layout of the analog and digital sections should be

separated to reduce interference from noise. To further
guard against unwanted noise, it is recommended to
bypass, as close as possible, the voltage supply pins to
their respective ground pins with 1µF tantalum and 0.01µF
ceramic disk capacitors in parallel.

3. The input capacitance of the analog input is much smaller

than that of a typical flash A/D converter. It is necessary to
use an amplifier with sufficient bandwidth and driving power.
The analog input pins are separated internally, so they
should be connected together externally. If the ADC-304 is
driven with a low output impedance amplifier, parasitic
oscillations may occur.

These parasitic oscillations can be prevented by introducing
a small resistance of 2 to 10

between the amplifier output

and the ADC-304's A/D input. This resistance must have a
very low value of series inductance at high frequencies.

Note that each of the analog input pins is divided in this
manner with these resistances. Connect the driving amplifier
as close as possible to the A/D input of the ADC-304.

ADC-304

6. The analog input signal is sampled on the positive-going

edge of CLOCK. Corresponding digital data appears at the
output on the negative-going edge of the CLOCK pulse after
a brief delay of 31ns maximum (TDLH, TDHL). Refer to the
Timing Diagram (Figure 3) for more information.

7. Connect all free pins to ANALOG GND to reduce unwanted

noise.

The analog input range is equal to a 2V spread. The
voltage on V

-V

will equal 2V. The connection of V

and

ANALOG GND is 2V higher than V

. Whether using a

single or dual power supply, the analog input will range from
the value of V

to V

. If V

equals +5V, then V

will equal

+3V and the analog input range will be from +3 to +5V.

4. The voltage between V

and V

is equivalent to the dynamic

range of the analog input. Bypass V

to ANALOG GND

USING a 1µF and a 0.01µF capacitor in parallel. To balance
the characteristics of the ADC-304 at high frequencies,
bypass V

with a 0.01µF capacitor to ANALOG GND.

Also, V

can be used as a trimming pin for more precise

linearity compensation. A stable voltage source with a
potential equal to V

and a 1k

potentiometer can be

connected to V

as shown in Figure 2 for this purpose.

5. Separate the clock input, CLOCK, from other leads as much

as possible, observing proper EMI and RFI wiring
techniques. This reduces the inductive pick-up of this lead
from interfering with the "clean" operation of the ADC-304.

Figure 3. ADC-304 Timing Diagram

Figure 2.

Improving Linearity Compensation

0.01µF

+5V

ANA GND

DUAL SUPPLY OPERATION

ADC-304

0.01µF

SINGLE SUPPLY OPERATION

N DATA VALID

CLOCK

COMPARATOR

OUTPUT

N(1)

N(2)

N(3)

31ns max.

TDLH

TDHL

N(2) DATA VALID

N(1) DATA VALID

6-BIT LATCH OUTPUT

DATA OUTPUT

BITS 1-8

TPW0

TPW1

ANALOG

INPUT

22ns
max.

31ns max.

TDLH

TDHL

22ns
max.

MINV

(TTL LEVEL)

ANALOG INPUT

0 to 2V

BIT 8

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

CLOCK

LINV

(LSB)

(MSB)

+5V

BIT 6

BIT 7

(LSB) BIT 8

CLOCK

ANA GND

N.C.

ANA IN

N.C.

ANA IN

N.C.

ANA GND

MINV

BIT 5

LINV

DIG GND

+5V

5.2V

+5V

DIG GND

BIT 4

BIT 3

BIT 2

BIT 1(MSB)

5.2V

MINV

(TTL LEVEL)

ANALOG INPUT

+3 to +5V

BIT 8

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

+3V

CLOCK

(LSB)

(MSB)

+5V

BIT 6

BIT 7

(LSB) BIT 8

CLOCK

ANA GND

N.C.

ANA IN

N.C.

ANA IN

N.C.

ANA GND

MINV

BIT 5

LINV

DIG GND

+5V

5.2V

+5V

DIG GND

BIT 4

BIT 3

BIT 2

BIT 1(MSB)

LINV

Figure 4. Connections for +5V Power Supply Operation

Figure 5. Connections for ±5V Power Supply Operation

APPLICATION CIRCUITS

Straight

Complementary

Two's

Complementary

Binary

Two's Complement

Complement

Binary

Unipolar

MINV

Scale

LINV

+FS 1SLB

+4.9922V

11111111

10000000

01111111

00000000

+7/8FS

+4.7500V

11011111

10100000

01011111

00100000

+3/4FS

+4.5000V

10111111

11000000

00111111

01000000

+1/2FS

+4.0000V

01111111

00000000

11111111

10000000

+1/4FS

+3.5000V

00111111

01000000

10111111

11000000

+1/8FS

+3.2500V

00011111

01100000

10011111

11100000

+1LSB

+3.0078V

00000001

01111110

10000001

11111110

Zero

+3.0000V

00000000

01111111

10000000

11111111

Table 2. Output Coding for ±5V Power Supply Operation (0 to 2V Signal Input)

Straight

Complementary

Two's

Complementary

Binary

Two's Complement

Complement

Binary

Unipolar

MINV

Scale

LINV

Zero

0.0000V

11111111

10000000

01111111

00000000

1LSB

0.0078V

11111110

10000001

01111110

00000001

1/8FS

0.2500V

11011111

10100000

01011111

00100000

1/4FS

0.5000V

10111111

11000000

00111111

01000000

1/2FS

1.0000V

01111111

00000000

11111111

10000000

3/4FS

1.5000V

00111111

01000000

10111111

11000000

7/8FS

1.7500V

00011111

01100000

10011111

11100000

FS + 1SLB

1.9922V

00000000

01111111

10000000

11111111

Table 1. Output Coding for +5V Power Supply Operation (+3 to +5V Signal Input)

NOTE: 28-pin DIP package shown

ADC-304

ADC-304

MECHANICAL DIMENSIONS

MODEL

PACKAGE

ADC-304

28-pin DIP (plastic)

ADC-304-3

28-pin SOP (plastic)

ADC-304-3

28-Pin SOP (Plastic)

ADC-304

28-Pin DIP (Plastic)

ADC-304

1.494 ±0.010
(37.95 ±0.25)

0.022 ±0.004

(0.55 ±0.10)

0.100 TYP.

(2.540)

0.051 ±0.006

(1.30 ±0.15)

0.187 ±0.010

(4.75 ±0.25)

0.118 MIN.

(3.0 MIN.)

0° to 15°

0.011 ±0.003
(0.28 ±0.08)

0.52 ±0.02
(13.2 ±0.3)

0.600

(15.24)

SEATING

PLANE

0.020 MIN.

(0.50 MIN.)

ADC-304

0.018 ± 0.004

(0.45 ± 0.1)

0.090 ±0.011

(2.30 ±0.28)

0.30 ±0.01

(7.7 ±0.2)

0.366

(9.3)

0.006 ±0.003

(0.15 ±0.08)

0.050 TYP.

(1.270)

0.41 ±0.02
(10.3 ±0.4)

0.020 ±0.008

(0.5 ±0.2)

0.746 ±0.010
(18.95 ±0.25)

0.007 ±0.005

(0.18 ±0.13)

ORDERING INFORMATION

IN N O VA T IO N a n d E X C E L L E N C E

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 / Fax: (508) 339-6356
For immediate assistance: (800) 233-2765

DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein
do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.

DS-0075B

10/96

DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 1-34-60-01-01
DATEL GmbH Munchen, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025

ISO 9001

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